For me, the two most important parts of a synth is sound quality and ease of use. And there is NO DOUBT that Vital ticks these boxes! There are another couple of aspects too, but these two are the most important.
I discovered and downloaded this synth for free a couple of days ago, tried it a bit, watched a few video tutorials, and thought hmmm, this is quite impressive!.. But I already got Serum.
But, I could not really stay away from Vital. So I set out at three different occasions to make a detailed comparison with Serum to find out if I “need” Vital too. 
But I never managed to finish a detailed comparison between these two synths - as soon as I open Vital, my mind goes “what if I…” and I start playing around. It seems like I can’t open Vital without starting to make my own patches - IT IS WAY TOO FUN TO USE! And that is in my book the best testament to a synth!
Needless to say, I bought the Pro version.
Congratulations and big thumbs up for this synth and its developers - may this synth prosper for years to come!
/Sven